I'm guessing a lot of LT's struggles stem from invalidation developmentally, so more invalidation isn't going to help anything. You can only stay and work it out if the other person is up to the task. This is why a lot of people end up having to become estranged from their subpar parents rather than work the original problems through with them. It isn't really running away if the parent is hurting you and refusing to truly, deeply understand your perspective before they even think about bringing their own feelings into it.

Healing developmental trauma is way different from handling normal adult relationships, which is why people ask therapists -- not friends or partners -- to help them do it. Yes, you likely develop interpersonal skills along the way, but that isn't where you start. (There are a ton of parallels with healthy parenting here. Is it helpful to guide your kid away from doing something that is likely to annoy others? Sure. Is it helpful to share the full breadth and depth of your white-hot irritation in the moment without considering the impact it might have on your kid? Definitely not.)

I think the boundaries conversation is fascinating because it sounds like Dr. T really broke the fourth wall in a dramatic fashion in the last few sessions. Part of him getting sucked into the old pattern is that he "allowed" LT to get under his skin and then turned it around and blamed her for his irritation. Total reenactment in the guise of him being "honest."

I've talked to my T before about how she handles the more challenging aspects of clients' reactions and testing, and she had some really clear things that she does or knows about herself to keep her from going to that place of overwhelm or annoyance. She basically won't let the client blow up the relationship. But that comes from a lot of training, supervision, self-care, and personal therapy, and a good sense of how she personally can be most effective as a therapist. Hopefully there is a good trauma-knowledgeable therapist out there who can do this kind of thing for you, LT. Validation is not bad when it's wielded by somebody who can ultimately work alongside you to help change your patterns.